Properties of Fluorocarbons

Grosse, A. V.; Cady, George H.

doi:10.1021/ie50447a627

Cited by 66 publications

(39 citation statements)

References 7 publications

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“…The pure liquid densities were taken from Dias et al 14,27,28 The dynamic viscosity data were compared with the literature data whenever possible. [16][17][18] The relative deviations between the dynamic viscosities measured in this work and those reported by other authors are presented in Figure 1. Deviations in the range (5 to 13) % are observed and are fairly constant in the studied temperature interval, with the exception of the highest temperature.…”

Section: Resultssupporting

confidence: 52%

“…[16][17][18] In the framework of our project concerning the aeration improvement of multiphase biological reactors, 19 it was found to be important to have new and high-quality viscosity data for these compounds that could only be achieved due to the highpurity compounds available nowadays. In this work, kinematic viscosities were measured, as a function of temperature, using an Ubbelohde viscometer for linear, cyclic, aromatic, and one R-substituted PFC.…”

Section: Introductionmentioning

confidence: 99%

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Viscosities of Liquid Fluorocompounds

et al. 2008

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In spite of their interest, viscosities of fluorocarbon compounds are scarce, and the available data are unreliable and of poor accuracy. In this work, viscosity measurements of linear, cyclic, aromatic, and R-substituted perfluorocarbons were carried out in the temperature range between (298.15 and 318.15) K using an Ubbelohde viscometer. The experimental results show that fluorinated compounds present viscosities considerably higher than their hydrocarbon homologues as expected. The viscosities increase from linear to aromatic to cyclic perfluorocarbons and within each family with the molecule size. The R-fluorine substitution by bromine increases the fluorocarbon viscosity due to the molecular weight increase. The Sastri-Rao method, a group contribution method for the liquid viscosity prediction, was applied for all the fluorocarbons where the viscosity was experimentally measured in this work. Using the new experimental data from this work, new group contribution values are proposed for fluorocarbon compounds allowing for a reduction of the average relative deviation from 12.0 % to 1.3 %.

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Section: Resultssupporting

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Viscosities of Liquid Fluorocompounds

et al. 2008

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“…18 Ethers are among the few good solvents for perfluoroalkyl derivatives and the unusual solubility of tetraarylporphyrins I and 2 in Et20, DME and t-butyl methyl ether (MTBE) can be ascribed to the favourable interaction of these solvents with the RF tails. 19 The remarkable high solubility of 2 in a wide range of solvents is related to the low degree of symmetry of this compound which in addition was synthesized as a mixture of atropoisomers. In this case too, ethers were found to be good solvents and, rather interestingly, even cyclohexane is able to solubilize 2 at low concentration.…”

Section: Chomentioning

confidence: 99%

Towards epoxidation catalysts for fluorous biphase systems: Synthesis and properties of two Mn(III)-tetraarylporphyrins bearing perfluoroalkylamido tails

et al. 1996

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Abstract:Two new Mn(lll)-tetraarylporphyrins Mn-I and Mn-2 bearing one amido-bonded n-C7F15 chain on each meso-aryl group have been synthesized. The presence of four perfluoroalkyl tails strongly influences the solubility of these compounds in common organic solvents, but it is not sufficient to impart solubility in fluorocarbons. The catalytic activity of the new complexes was tested in alkene epoxidations employing aqueous NaOCI as oxygen donor. Results show that Mn-2 is more active than Mn(lll)-5,10,15,20-tetrakis-(2,6-dichlorophenyl)porphyrin, one of the most efficient porphyrinic catalysts for hydrocarbon oxygenation. Copyright © 1996 Published by Elsevier Science Ltd Fluorocarbons (perfluorinated alkanes, ethers and tertiary amines) have peculiar chemical and physical properties which are potentially exploitable in many technological fields. 1 Advantages in using these compounds as inert media for chemical reactions (e.g. esterification, 2 photolysis, 3 bromination of alkenes 4 and oxidation of organozincs to hydroperoxides 5) have been pointed out. A new approach to liquid biphasic catalytic reactions based on the low miscibilities of fluorocarbons with most organic solvents has been recently described by Horv~ith and R~ibai. 6 In what these authors define as "Fluorous Biphase System" (FBS) the catalyst is confined to the fluorocarbon phase, whereas substrate/s and product/s are dissolved in a common organic solvent.Reactions can be carried out in the resulting biphasic system, but it is also possible to work under homogeneous conditions by increasing the temperature. At the end of the reaction the catalyst can be easily recovered, after cooling, by simple phase separation and it becomes at once available for further use. Despite the opportunities offered, this approach has been applied only to hydroformylation of olefins: extension to other reactions calls for the availability of efficient "ad hoe" catalysts soluble in fluorocarbons. Insertion of perfluoroalkyl segments in the structure of known active compounds has been proposed as a general solution for the problem, 6 but, despite apparent simplicity, concrete application of this strategy is still a challenge.Hydrocarbon oxygenation is a highly attractive field for application of the FBS concept. Therefore we are currently engaged in a program aimed at the synthesis of catalysts that will serve this purpose. In this article we describe the synthesis of two tetraarylporphyrins 1 and 2 ( Metallo-tetraarylporphyrins are well-known catalysts for hydrocarbon oxygenation. 7 The functionalization of the macrocyclic ligand by linking perfluoroalkyl tails was reasonably expected to impart fluorophilic character to this class of compounds. Furthermore, the introduction of strong electron-withdrawing perfluoroalkyl chains (RF) could alter the electronic properties of the complexes and it should favourably affect their stability and catalytic efficiency. The presence of electron-withdrawing groups on the meso-aryl substituents and/or in the 13-pyrrolic positions...

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“…Boron fluoride was reported by Von Grosse and Cady [7] to cause the slow polymerization of tetrafluoroethylene at room temperature to a solid polymer resembling Teflon . In the present study two concentrations were prepared in Pyrex tubes and left for periods of 6 to 18 months.…”

Section: Peroxides and Azo-bis(isobutyronitrile)mentioning

confidence: 98%

“…Von Grosse and Cady [7] report that tetrafluoroethylene is polymerized by boron fluoride and niobium pentafluoride . The niobium pentafluoride polymerization was r eported to resemble the action of aluminum chloride on ethylene, i. e., a rapid reaction leading to low molecular weights ; the boron fluoride reaction was reported to proceed slowly, yielding in several days at room temperature a high polymer r esembling Teflon.…”

Section: Polymerization Of Tetra£luoroethylenementioning

confidence: 99%

Factors affecting the thermal stability of polytetrafluoroethylene

Florin¹,

Wall²,

Brown³

et al. 1954

J. RES. NATL. BUR. STAN.

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The structure and kinetics of thermal decomposition of polytetrafluol'oethylene suggestcd sev eral m ethods for impro vemcnt of its stability: (a) p olym crization in the presen ce of fluor oca rbo~l catalysts or ph<;>to?hemically to eliminate labile centers for initiation. (b) incluSlOn of foreIg n structural UllitS III the polymer to promote chain t ransfer of t.he free radicals active in d epolymcrization, (c) inclusion of foreign m olecules capable of promoting chain transfer . . The catalysts t ri ed inclu?ed perfluorodimeth ylmcrcury, perfluoromethyl iodide, and fl uorme gas, as well as convent.lOnal catalysts. The foreign structural units and a dditiv~s included .sulfur, seleni um, and a vari ety of hydrocarbon and fluorocarbon groups, maml.y aromatIC, addcd usuall y as dibromides to t he polymerizing mixtme. None of thc cxpeflmental catalysts or additives brought about any change in the rate of thermal d ecomposition.

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Properties of Fluorocarbons

Cited by 66 publications

References 7 publications

Viscosities of Liquid Fluorocompounds

Viscosities of Liquid Fluorocompounds

Towards epoxidation catalysts for fluorous biphase systems: Synthesis and properties of two Mn(III)-tetraarylporphyrins bearing perfluoroalkylamido tails

Factors affecting the thermal stability of polytetrafluoroethylene

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